The
XAllocSizeHints function allocates and returns a pointer to a XSizeHints
structure. Note that all fields in the XSizeHints structure are initially
set to zero. If insufficient memory is available, XAllocSizeHints returns
NULL. To free the memory allocated to this structure, use XFree.

The XSetWMNormalHints
function replaces the size hints for the WM_NORMAL_HINTS property on
the specified window. If the property does not already exist, XSetWMNormalHints
sets the size hints for the WM_NORMAL_HINTS property on the specified
window. The property is stored with a type of WM_SIZE_HINTS and a format
of 32.

XSetWMNormalHints can generate BadAlloc and BadWindow errors.

The XGetWMNormalHints function returns the size hints stored in the
WM_NORMAL_HINTS property on the specified window. If the property is of
type WM_SIZE_HINTS, is of format 32, and is long enough to contain either
an old (pre-ICCCM) or new size hints structure, XGetWMNormalHints sets
the various fields of the XSizeHints structure, sets the supplied_return
argument to the list of fields that were supplied by the user (whether
or not they contained defined values), and returns a nonzero status. Otherwise,
it returns a zero status.

If XGetWMNormalHints returns successfully and
a pre-ICCCM size hints property is read, the supplied_return argument will
contain the following bits:

If the property is large enough to contain the base size and window gravity
fields as well, the supplied_return argument will also contain the following
bits:

0
0>=40 .vs 0u
0<=39 .vs 0p
PBaseSize|PWinGravity

XGetWMNormalHints can generate a PN BadWindow error.

The XSetWMSizeHints
function replaces the size hints for the specified property on the named
window. If the specified property does not already exist, XSetWMSizeHints
sets the size hints for the specified property on the named window. The
property is stored with a type of WM_SIZE_HINTS and a format of 32. To set
a window's normal size hints, you can use the XSetWMNormalHints function.

XSetWMSizeHints can generate BadAlloc, BadAtom, and BadWindow errors.

The XGetWMSizeHints function returns the size hints stored in the specified
property on the named window. If the property is of type WM_SIZE_HINTS,
is of format 32, and is long enough to contain either an old (pre-ICCCM)
or new size hints structure, XGetWMSizeHints sets the various fields
of the XSizeHints structure, sets the supplied_return argument to the
list of fields that were supplied by the user (whether or not they contained
defined values), and returns a nonzero status. Otherwise, it returns a
zero status. To get a window's normal size hints, you can use the XGetWMNormalHints
function.

If XGetWMSizeHints returns successfully and a pre-ICCCM size
hints property is read, the supplied_return argument will contain the
following bits:

The x, y, width, and height members are now obsolete and are left solely
for compatibility reasons. The min_width and min_height members specify
the minimum window size that still allows the application to be useful.
The max_width and max_height members specify the maximum window size. The
width_inc and height_inc members define an arithmetic progression of sizes
(minimum to maximum) into which the window prefers to be resized. The min_aspect
and max_aspect members are expressed as ratios of x and y, and they allow
an application to specify the range of aspect ratios it prefers. The base_width
and base_height members define the desired size of the window. The window
manager will interpret the position of the window and its border width
to position the point of the outer rectangle of the overall window specified
by the win_gravity member. The outer rectangle of the window includes any
borders or decorations supplied by the window manager. In other words, if
the window manager decides to place the window where the client asked,
the position on the parent window's border named by the win_gravity will
be placed where the client window would have been placed in the absence
of a window manager.